It is perhaps the best unsatisfactory answer to meeting the country's voracious power needs. While promising cleaner air and less reliance on foreign energy, the nation's 104 mostly aging nuclear power plants still spur safety worries over radiation leaks and unanswered questions over what to do with the long-term radioactive waste from spent fuel rods.

The growing crisis in Japan is reigniting that U.S. debate over the role of nuclear power while reviving memories of Pennsylvania's Three Mile Island in 1979, the biggest commercial nuclear accident in this country. The ramifications have already rippled across the globe, raising safety concerns anew and prompting countries such as Germany and Switzerland to curtail planned nuclear plant expansions.

Locally, the threat of multiple, partial meltdowns in Japan won't help the nuclear cause.

For Progress Energy, which provides electricity to much of Central Florida, Japan's troubles come on the eve of the power company's acquisition by fellow pro-nuke energy provider Duke Energy. Progress Energy wants to build four new nuclear reactor units: two in Florida's Levy County and two near Raleigh, N.C. The proposed plants would raise the number of Progress Energy nuclear units to nine in five locations from its current five in four locations. The new plants would be a different design from the damaged GE nuke plants jeopardizing Japan.

"It is premature for us to comment on the unfolding events in Japan," said Progress Energy spokeswoman Jessica Lambert.

Progress Energy wants to build Westinghouse AP1000 nuke plants. The Nuclear Regulatory Commission soon will approve the AP1000, including its different containment design. But one congressman, Rep. Edward J. Markey, D-Mass., first wants the NRC to resolve a concern with one of its own senior structural engineers, John S. Ma, over whether a shield building in the new design could withstand an earthquake or the impact of an airplane crash.

A big earthquake or tsunami seems unlikely in west-central Florida. Since 9/11, however, the threat of an airplane used by terrorists to target a nuke plant is no longer considered a far-flung possibility. Markey, citing NRC engineer Ma, suggests that under heavy stress the AP1000 shield building could shatter "like a glass cup."

The bottom line is that the U.S. revival of nuclear power, which gathered steam some five years ago, was struggling even before Japan renewed talk about meltdowns.

That was not the original plan. The George W. Bush administration got bullish on nuclear power as the answer to future electricity needs and many environmental issues. But the process bogged down even as many power companies sought federal support.

While President Obama has called for tripling federal loan guarantees for nuclear power to $54 billion, the fate of Japan's damaged nuclear plants will stiffen resistance to such funding.

Where does this all leave us? Wishing for nuclear power, but fearful of pulling the trigger.